# Alignments of parity even/odd-only multipoles in CMB

## TL;DR

This study analyzes parity asymmetries in the CMB multipoles from PLANCK data, finding significant alignments in odd multipoles but not in even ones, suggesting potential anisotropy features.

## Contribution

It introduces directional statistics to compare parity even and odd multipoles and assesses their alignments, providing new insights into CMB anisotropy patterns.

## Key findings

- No significant alignments in even multipoles.
- Evidence for alignments in odd multipoles at ~2 sigma significance.
- Alignment axes are consistent across different galactic cuts.

## Abstract

We compare the statistics of parity even and odd multipoles of the cosmic microwave background (CMB) sky from PLANCK full mission temperature measurements. An excess power in odd multipoles compared to even multipoles has previously been found on large angular scales. Motivated by this apparent parity asymmetry, we evaluate directional statistics associated with even compared to odd multipoles, along with their significances. Primary tools are the \emph{Power Tensor} and \emph{Alignment Tensor} statistics. We limit our analysis to the first sixty multipoles i.e., $l=[2,61]$. We find no evidence for statistically unusual alignments of even parity multipoles. More than one independent statistic finds evidence for alignments of anisotropy axes of odd multipoles, with a significance equivalent to $\sim 2 \sigma$ or more. The robustness of alignment axes is tested by making galactic cuts and varying the multipole range. Very interestingly, the region spanned by the (a)symmetry axes is found to broadly contain other parity (a)symmetry axes previously observed in the literature.